The invention relates to a coupling shaft for transmitting a torque from the power take-off of a driving machine, for instance an agricultural tractor, to the input shaft of a driven machine, for instance an agricultural machine, which shaft is provided with at least one universal joint, such as a cross connection, wherein the shaft is protected by a tube of fitting material which is mounted on the shaft by means of a bearing ring which protrudes into a groove of the shaft and is connected to a cover which is fixed to the tube and which projects over the universal joint.
The above stated coupling shafts normally lie free between the driving and driven machine so that for safety purposes it is necessary to arrange a protective tube therearound which is stationary. This is difficult on account of the bearing mounting. The relatively dangerous universal joints are guarded by a cover projecting thereover.
The assembly of such protective constructions round the drive shaft are quite complicated even though many proposals for simplification have already been made.
The invention has for its object to provide a very simple-assembly for performing without auxiliary tools and having comparatively few separate components, while retaining a durable operation under heavy conditions, wherein for safety reasons disassembly is not possible other than with use of tools, so that undesired disengagement is impossible.
The coupling shaft according to the invention is distinguished in that the bearing ring is provided with at least two cam-like protrusions arranged along the periphery of the ring at a mutual distance and the cover is provided with at least two spaces in each case for receiving these protrusions, wherein by an angular displacement of the bearing ring relative to the cover a locking in axial sense is effected between cover and bearing ring, and wherein a closely-sized locking member is active between cover and bearing ring to counter an opposite rotation of this bearing ring.
Due to the closely-sized locking member, by which is meant that this is received closely-sized in the cover, it is possible to determine immediately that the assembly operations have been carried out correctly and that the cover is properly positioned in relation to the bearing ring.
According to a further development the locking member is formed by an insert piece which can be locked into a recess of the cover and which is provided with a passage opening for lubrication purposes. A dual function is herewith created in simple manner for the insert piece, which serves, on the one hand, to secure the correct position of the bearing ring in the cover and, on the other, to feed fats or oils to the bearing ring close to the shaft rotating therein.
Moreover, due to the isolation of the lubrication function in a separate insert piece, the manufacture of the cover is considerably simplified. The insert piece can further be embodied as standard component which can be applied in covers of different dimensions.
In another embodiment the locking member is a ring which is connected rotatably and slidably to the cover and which is at least provided with two or more axially directed locking lips which lock the protrusions into the recesses of the cover in the correct position. This bearing ring can also be provided with a passage for the lubricant.